Answer 1

The product of the reaction is Phthalic Anhydride.

Answer 2

Phthalic acid, an ortho-dicarboxylic acid, undergoes intramolecular dehydration when heated. One molecule of water is eliminated, resulting in the formation of a stable five-membered cyclic anhydride, known as phthalic anhydride.

Reaction: Phthalic acid on heating ($\Delta$) yields phthalic anhydride and water.

Structure of Reactant (Phthalic Acid): O=C(O)c1ccccc1C(=O)O

Structure of Product (Phthalic Anhydride): O=C1OC(=O)c2ccccc12